The effect of frightened status is different.
Frightened status (RAW):
A frightened creature has disadvantage on Ability Checks and Attack rolls while the source of its fear is within line of sight.
The creature can’t willingly move closer to the source of its fear.
I believe BG3 forces frightened creatures run away and prevent them from using any action. (If they didn't change it recently.)
The effect I see when I use menacing attack, is a little visual effect around their head, and they stand in place cowering not being able to attack.
